Wiring Color Codes - University of Illinois Extension
Wiring Color
Codes
for McLean County 4-H Projects
Common colors for DC wire
Black
White
Red
DC Battery Connections
Black wire always to negative terminal
White wire always to positive terminal
DC Connections
Black wires identify negative or hot wires. Switches connect on negative side of battery to the load (light).
White wire is used to identify the positive polarity.
White
Black
Switch
Black
This Knife switch shows black wire in and black wire out.
Black
This type of miniature lamp socket has a brass colored screw and a silver screw.
Black wires will connect to brass and white wires connect to silver.
Red wire is also like black and can be used to identify the negative side or switch side of a circuit.
This is a 3-way circuit. Red and black wires are used to identify the path of current and are on the negative side.
Black
Black
White
Black
3-way switch
Red
This is a 3-way/4-way circuit. Red and black wires are used to identify the path of current and are on the negative side.
4-way switch
The lights are in series. The black wire in between the lights could also be red.
Black
Common Wire for AC
Type 1
Romex Cable
2 conductor with a ground
Black
Ground
White
Common Wire for AC
Type 2
Black
Romex Cable
3 conductor with a ground
White
Red
Ground
AC Connections
Wiring an Outlet
Ground green terminal
White silver terminal
(neutral)
Black
(hot)
Outlet other side:
Black wire on brass terminal (hot)
AC Connections
Wiring a Switch
Black (hot)
Black (hot)
Ground green terminal
Neutrals tied together
AC Connections Wiring a 3-way switch
Wiring of a 3-way switch using 3 conductor Romex cable. This is an exception where white can is terminated on the switch and is a
HOT (live) wire!
A closer look a the 3way switch. Notice the dark screw, that is the common position.
The other side of the
3-way switch.
